IGM Biosciences announces update on IGM-8444 Phase 1 trial

IGM Biosciences announced an update on its clinical development program for IGM-8444, a novel multivalent DR5 agonist, and announced plans for a new randomized combination trial in patients with metastatic colorectal cancer. Initial Phase 1 data reported from a cohort of patients with combination treatment of IGM-8444 and FOLFIRI showed an encouraging safety profile which was broadly comparable to that expected from chemotherapy alone in this setting. Specifically, there was no drug related clinically significant hepatotoxicity, with only grade 1 and grade 2 transient liver enzyme elevations observed. In patients with metastatic colorectal cancer, the combination of IGM-8444 and FOLFIRI showed promising activity, with multiple confirmed responses observed even in patients who had previously progressed on FOLFIRI. In 13 metastatic patients treated with doses of IGM-8444 from 1 to 10 mg/kg plus standard doses of FOLFIRI chemotherapy, there were four responses observed, and one additional patient had substantial tumor shrinkage allowing for subsequent complete surgical resection. Responses occurred in patients with KRAS wild type and mutated tumors and in patients with or without liver metastases. The majority of patients were on their third line of treatment or beyond and 10 of the 13 patients had previously been treated with FOLFIRI chemotherapy. Median progression free survival among nine 3L+ patients was 5.5 months, with the longest observed PFS extending beyond 12 months. Based on these results, the Company is initiating a randomized trial in second line patients with metastatic colorectal cancer to assess the additional benefit of IGM-8444 combined with the current standard of care regimen of FOLFIRI and bevacizumab. This open label trial is planned to begin in Q1 2023. "These initial IGM-8444 clinical results represent an important step in demonstrating the potential of our IgM antibody platform to overcome the long history of failure with conventional IgG antibodies targeting DR5," said Fred Schwarzer, Chief Executive Officer of IGM Biosciences. "We believe these results also help support the potential for IgM antibodies as agonists against the broader TNF receptor super family, and we look forward to accelerating our company-wide efforts to develop a new class of agonist antibody medicines, including through our collaboration with Sanofi."